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1995 johnson 150hp

T

TJ

Guest
"My motor starts and runs perf

"My motor starts and runs perfect for about 3min at idle. After that the prime ball gets very soft and the motor will die. Motor ran perfect the first time out this year and just happened today. I can prime the ball at the dock and it will get rock hard. But when i start the boat and get it up to speed, she'll bog right down and stall. after she stalls i primed the ball and the motor will start right back up until ball goes mush again. I checked all hoses and replaced most clamps on all fuel lines. I also checked my air vent on my internal fuel tank. I can't see any kinks in any hoses either. Is this most likely a fuel pump? Thanks for all help and time. T.J. (Michigan)"
 
"I don't know how it could

"I don't know how it could be the fuel pump if the bulb is going soft. It seams to be sucking the fuel from the bulb! Maybe the vent is blocked with a bug or something, can you run it without the gas cap on?"
 
"I tried to run it with the ga

"I tried to run it with the gas cap off and it's doing the same thing. Also, I just drained all carbs at the bottom srews(looking for water) and it's doing the same thing. I replaced fuel filter and made sure the cone filter on the fuel pump was clean. It will start up fine the bulb starts to get soft and the motor seems like it's running on 2 cylnders then sputters and stalls. Thanks fish for your time and direction. I'm just not sure where else to look. The boat is docked right behind my house so i'll try anything before i have to pull the thing out of the water. Thanks again T.J."
 
"Well just to update the board

"Well just to update the board...I replaced my prime bulb and that didn't help either. I took my floor completly up and checked all hoses and clamps. they all seem to be in perfect condition. Once again i'm back to square one. I'll prime the ball, start the motor and let her idle. After about 3min the motor will shut right off(as if it was running out of gas) My tank has 50 gallons in it right now. Thanks a lot guys for any help or ideas(you all helped me out tons last year). Good Friday to all."
 
"TJ,

If the primer was the


"TJ,

If the primer was the problem, the engine would run normally if you squeezed the ball while it was running. This would probably help if the fuel pump was the problem also.

I would take a look at the float in the vapor separator. You may have a clog in there.

Tony"
 
"Thanks Tony for your suggesti

"Thanks Tony for your suggestion. I'm not too sure on where the vapor separator is at but i'll try to research and see. So, I should squezze the ball while it's running and see if it stalls out? I just now took her for a ride...i primed the ball(rock hard) started off slow(idled perfect) took her up to around 3500rpm and was up to speed... Then, it boged right down to under 1000rpm and stayed running. I primed the ball, it sputtered pretty good but started running perfect. I got her up on plane again and it did the same thing. all i know is all hoses, clamps, vents, and gaskets are all perfect or new. I had all carbs rebuilt last year. I'm also thinking about taking the neck off the fuel tank and see if it's clogged at the bottom of the tank? Thanks for any help guys T.J."
 
"The primer bulb going as you

"The primer bulb going as you say "mush" is normal if by "mush" you're saying that the bulb simply isn't hard anymore. Most bulbs lay horizontal and the the fuel will drop down to the halfway level of the bulb. No, I don't know why but trust me, it's normal.

However, if by "mush" you're saying that the bulb actually goes flat, then you have a fuel restriction at some point between the bulb and the fuel supply.

If all of the above is okay, and they're no fuel/air leaks between the fuel pump and the fuel supply, the most likely cause of the problem would be no pulse (pressure/vacuum) being delivered to the fuel pump by the associated cylinder (leaking/broken pulse hose, crankcase leak, blown piston), or a failed fuel pump."
 
"Hey TJ...Try this...Under the

"Hey TJ...Try this...Under the VRO pump there are three hose connections...One is the oil supply, one is the fuel supply, and the third is the pluse limiter... A hose runs from this to a fitting in the block...inspect this hose and see if its off or damaged in any way..If all is good there, replace the limiter..inexpensive and can be gotten at any dealer...Post back and let us know what you find..."
 
"Take a 5 gallon marine fuel c

"Take a 5 gallon marine fuel can with you next time. Hook it up, prime it & try that. If your problem is solved, then you have a restriction between the primer and the tank. I also wonder what kind of shape the pick-up in the tank is in. The old 5 gallon can routine will tell you alot."
 
"great ideas guys and as soon

"great ideas guys and as soon as i recover from lastnight i'm gonna try all these ideas. The prime ball dosen't go flat but it doesn't have any gas in it after the boat stalls. So I have to prime it to get more gas up to the motor. Thanks again guys, T.J."
 
"Well first I checked the hose

"Well first I checked the hoses around the pulse limiter and didn't find anything wrong with the hoses. I also took a 6gal tank and tried that too. The tank didn't help anything either, but atleast i know I don't have a fuel restriction problem from the tank. On Monday i'm going to buy a limiter and try that. I haven't had a chance to check around the vapor seperater but will also try that. I realized that after the boat stalls the ball doesn't have any fuel in it at all. Thank you guys so much for your help. It really means a lot to me and i'll try to help anyone else from my experience. Have a good Easter. T.J."
 
I was having same proplem as y

I was having same proplem as you are and I finally found that i had a torn diafram in fuel side of VRO pump you can test the pump with a vacum pump it is not to hard it would help if you had a book and follow what it say on testing it. I rebuilt my VRO pump and motor starts right up and runs great now
 
Thanks for your information Jo

Thanks for your information John... I'll check that out first thing Monday too and let you know.
 
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